Tactile Sensor Without Wire and Sensing Element in the Tactile Region Using New Rubber Material

In this paper, a force sensing element having a pillar and a diaphragm is proposed and thereafter fabricated by micromachining. Piezo resistors are fabricated on a silicon diaphragm for detecting distortions caused by a force input to a pillar on the diaphragm. Since a practical arrayed sensor consisting of many of this element is still under development, the output of an assumed arrayed type tactile sensor is simulated by FEM (finite element method). Using simulated data, the possibility of tactile pattern recognition using a neural network (NN) is investigated. The learning method of NN, the number of units of the input layer and the hidden layer, as well as the number of training data are investigated for realizing high probability of recognition. The 14 subjects having different shape and size are recognized. This recognition succeeded even if the contact position and the rotation angle of these objects are changed.

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Tactile Object Recognition for Humanoid Robots Using New Designed Piezoresistive Tactile Sensor and DCNN

Sensors ◽

10.3390/s21186024 ◽

2021 ◽

Vol 21 (18) ◽

pp. 6024

Author(s):

Somchai Pohtongkam ◽

Jakkree Srinonchat

Keyword(s):

Object Recognition ◽

Humanoid Robot ◽

Sensor Array ◽

Recognition Rate ◽

Tactile Sensor ◽

Humanoid Robots ◽

Superior Performance ◽

Robot Hand ◽

Sensing Element ◽

Tactile Sensor Array

A tactile sensor array is a crucial component for applying physical sensors to a humanoid robot. This work focused on developing a palm-size tactile sensor array (56.0 mm × 56.0 mm) to apply object recognition for the humanoid robot hand. This sensor was based on a PCB technology operating with the piezoresistive principle. A conductive polymer composites sheet was used as a sensing element and the matrix array of this sensor was 16 × 16 pixels. The sensitivity of this sensor was evaluated and the sensor was installed on the robot hand. The tactile images, with resolution enhancement using bicubic interpolation obtained from 20 classes, were used to train and test 19 different DCNNs. InceptionResNetV2 provided superior performance with 91.82% accuracy. However, using the multimodal learning method that included InceptionResNetV2 and XceptionNet, the highest recognition rate of 92.73% was achieved. Moreover, this recognition rate improved when the object exploration was applied to demonstrate.

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Micromachined Planar Coil Tactile Sensor Implantable in Soft Structure

10.1115/imece2000-1070 ◽

2000 ◽

Author(s):

Nobuyuki Futai ◽

Takashi Yasuda ◽

Masayuki Inaba ◽

Isao Shimoyama ◽

Hirochika Inoue

Keyword(s):

Resonance Frequency ◽

Silicone Rubber ◽

Small Deformation ◽

Tactile Sensor ◽

Tactile Sensing ◽

Sensing Element ◽

Spiral Coil ◽

Resonance Frequencies ◽

Planar Coil ◽

Multiple Sensing

Abstract This paper describes design and fabrication of a small, thin and deformable tactile sensing unit including micromachined LC trap circuitry. One tactile sensing element consists of a capacitor and a planar spiral coil. Each element has own resonance frequency, and small deformation of the coil in the element is detected by measuring its frequency deviation. Only three wires are necessary to obtain signals from multiple sensing elements. Since the sensing elements do not need any substrate, they can be implanted in soft material. A prototype array of the sensing elements has been fabricated and tested. Seven-turn coils 1.5 mm in diameter have been obtained. Range of the resonance frequencies of the fabricated elements is 50 MHz – 170 MHz. Using a silicone rubber body in which a sensing element is embedded, push-in depth values are detected by resonance frequency deviations when a wax ball (3 mm in diameter) touches the silicone rubber body. On condition that the sensing element is embedded in standard silicone rubber, its frequency sensitivity is 0.15%/mm. In the frequency band 50 – 400 MHz, the experiment shows that a simultaneous measurement of not less than 20 elements can be done.

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Development of Fully Flexible Tactile Pressure Sensor with Bilayer Interlaced Bumps for Robotic Grasping Applications

Micromachines ◽

10.3390/mi11080770 ◽

2020 ◽

Vol 11 (8) ◽

pp. 770

Author(s):

Lingfeng Zhu ◽

Yancheng Wang ◽

Deqing Mei ◽

Chengpeng Jiang

Keyword(s):

Pressure Sensor ◽

Tactile Sensor ◽

External Pressure ◽

Robotic Hand ◽

Sensing Element ◽

Tactile Sensors ◽

Human Machine Interaction ◽

Tactile Information ◽

Sensing Range ◽

Intelligent Robotics

Flexible tactile sensors have been utilized in intelligent robotics for human-machine interaction and healthcare monitoring. The relatively low flexibility, unbalanced sensitivity and sensing range of the tactile sensors are hindering the accurate tactile information perception during robotic hand grasping of different objects. This paper developed a fully flexible tactile pressure sensor, using the flexible graphene and silver composites as the sensing element and stretchable electrodes, respectively. As for the structural design of the tactile sensor, the proposed bilayer interlaced bumps can be used to convert external pressure into the stretching of graphene composites. The fabricated tactile sensor exhibits a high sensing performance, including relatively high sensitivity (up to 3.40% kPa−1), wide sensing range (200 kPa), good dynamic response, and considerable repeatability. Then, the tactile sensor has been integrated with the robotic hand finger, and the grasping results have indicated the capability of using the tactile sensor to detect the distributed pressure during grasping applications. The grasping motions, properties of the objects can be further analyzed through the acquired tactile information in time and spatial domains, demonstrating the potential applications of the tactile sensor in intelligent robotics and human-machine interfaces.

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Crosstalk Reduction of Tactile Sensor Array with Projected Cylindrical Elastomer over Sensing Element

Japanese Journal of Applied Physics ◽

10.1143/jjap.50.06gm08 ◽

2011 ◽

Vol 50 (6) ◽

pp. 06GM08 ◽

Cited By ~ 8

Author(s):

Masayuki Sohgawa ◽

Tatsuya Uematsu ◽

Wataru Mito ◽

Takeshi Kanashima ◽

Masanori Okuyama ◽

...

Keyword(s):

Sensor Array ◽

Tactile Sensor ◽

Sensing Element ◽

Tactile Sensor Array ◽

Crosstalk Reduction

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Tactile Sensor without Wire and Sensing Element in the Tactile Region Based on EIT Method

2007 IEEE Sensors ◽

10.1109/icsens.2007.4388519 ◽

2007 ◽

Cited By ~ 35

Author(s):

Yo Kato ◽

Toshiharu Mukai ◽

Tomonori Hayakawa ◽

Tetsuyoshi Shibata

Keyword(s):

Tactile Sensor ◽

Sensing Element

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Development of a Conductive Polymer Based Novel 1-DOF Tactile Sensor with Cylindrical Arch Spring Structure Using 3D Printing Technology

Sensors ◽

10.3390/s19020318 ◽

2019 ◽

Vol 19 (2) ◽

pp. 318 ◽

Cited By ~ 1

Author(s):

Peshan Sampath ◽

Eranga De Silva ◽

Lakshitha Sameera ◽

Isuru Udayanga ◽

Ranjith Amarasinghe ◽

...

Keyword(s):

3D Printing ◽

Conductive Polymer ◽

Load Condition ◽

Tactile Sensor ◽

Maximum Load ◽

Sensing Element ◽

Element Analysis ◽

Printing Technology ◽

Critical Dimensions ◽

3D Printing Technology

Under this research, a novel tactile sensor has been developed using a conductive polymer-based sensing element. The incorporated sensing element is manufactured by polymer press moulding, where the compound is based on silicone rubber and has enhancements by silica and carbon black, with Silane-69 as the coupling agent. Characteristics of the sensing element have been observed using its sensitivity and range, where its results pose an inherent nonlinearity of conductive polymers. For the force scaling purpose, a novel 3D printed cylindrical arch spring structure was developed for this highly customizable tactile sensor by adopting commonly available ABSplus material in 3D printing technology. By considering critical dimensions of the structure, finite element analysis was carried out to achieve nearly optimized results. A special electrical routing arrangement was also designed to reduce the routing complexities. The optimized structure was fabricated using the 3D printing technology. A microcontroller-based signal conditioning circuit was introduced to the system for the purpose of acquiring data. The sensor has been tested up to the maximum load condition using a force indenter. This sensor has a maximum applicable range of 90 N with a maximum structural deflection of 4 mm. The sensor assembly weighs 155 g and the outer dimensions are 85 mm in diameter and 83 mm in height.

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